Restoration diary

Renown Repulse Restoration Group has placed an order with a noted locomotive electronics expert for testing of a CU1 main control units and the rebuild of KV10 load regulators using modern components.  The CU1 acts as the "central brain" of a Class 50, receiving and sending signals from and to all the other electronic control units in the locomotive.  There are two KV10 load regulators in a Class 50, one is denoted CU3 and controls the main generator output.  The other is denoted CU6 and controls the ETH generator.  A KV10 is transformed into a CU3 or a CU6 by means of pairing with a control card CU3A or CU6A.

As with many electronic components of the Class 50, the KV10 design is full of obsolete components and with an eye to the future we feel this work is essential to our goal of "future proofing" 50029 and 50030 and ensuring them a long and secure future in preservation.  The original design suffers from a tendency to "lock on", whereby faulty circuitry causes the CU3 to lock in the full position even if the power controller is at its minimum position.  The only real solution is to repair the faulty circuitry but that repair knowledge gets ever more scarce with the passing of time.  As a result, we feel that the decision to purchase four rebuilt units (one main and one ETH generator control unit for each of 50029 and 50030) is money well spent.

There are actually two sub-types of KV10, denoted B1 and B2 with slight differences in component types.  RRRG has over twice as many B1s as we do B2s but our stock of CU3A and CU6A cards are only confirmed to work with B2 type KV10s.  The rebuild process uses only the case, heat sink and thyristor from the original KV10 and as a result the control cards become obsolete as the components they contain are now integrated into the main unit.  We intend to supply type B1 KV10s for the rebuild project with a decision on disposal of the type B2 units and control cards to be taken at a later date.

The following two shots show a rebuilt CU6-type KV10 installed in 50008 Thunderer.  The first shot is taken from the Thin Man's side and the second is opposite the exhauster.  Click on either to enlarge (opens in new window).

Needless to say, this work will not be cheap and we really need the support of the preservation community.  Perhaps you could donate to our project, or become a member of RRRG and buy shares, or browse our online shop for items of interest?  Your support is what has got us this far already and it is much appreciated.

Apologies for the non-availability of the RRRG website earlier today.  This was caused by a hardware failure at our web hosting provider which has now been resolved and the site has been restored from a backup.

On 23rd and 24th February the RRRG sales stand attended the Nene Valley winter steam gala. The stand was predominantly coordinated and managed by Tim and myself; Mark was around on Saturday morning to bring stock down and help set up but couldn't stay because of a family appointment. It was cold. Very cold. So cold, in fact, that it was the first time in ten years of RRRG trading that we have had the sales stand out whilst snow has been falling... That said, it was nice to see a preserved line trying something new and trying to extend their operating season to make more money. Saturday trading was reasonable although in the afternoon the star attraction no 70000 Britannia unfortunately derailed at Yarwell Junction whilst backing onto coaching stock at the end of a run round manoeuvre. The non-availability of this locomotive undoubtedly affected attendance levels at the gala, which was a shame. We sold a mixture of items but no really high value items such as the boxed Hornby model sets you see in our online shop, sold, which was again a bit of a shame.

The final figures for sales were:

Saturday 23rd Feb: Total Turnover £161.55

Sunday 24th Feb: Total Turnover £137.25

Total RRRG profit after fees was £93.08 for the weekend, which was a respectable showing. Renown Repulse Universal, RRRG's commercial wing, also sold a number of items from the stand over the weekend to create profit which can be re-invested in RRRG and its activities (such as the hosting fees for this site!) and contributed to the putch fee.

Even though I fell ill late on Sunday evening with one of the worst colds I've had in many a year, doubtless aided by standing out on a freezing cold platform all weekend, it was still a worthwhile event and our thanks go to the Nene Valley Railway for inviting us to have a stand once again.

As long-term followers of RRRG will know, for some time now we have been investigating the remanufacture of CU2 field divert units to replace the ones missing from our locomotives.  Our contractors for the job, Industrial Electronic Services Ltd, had analysed a genuine CU2 kindly loaned to us by another Class 50 owner and were confident they could reproduce the circuitry and components in the unit, using modern equivalents where possible/necessary.  They had however hit quite a snag when it came to replacing the little relay in the original unit.  The CU2 is a really amazingly compact piece of equipment for mid-1960s electronics as seen in the photo of the loaned unit below.  The relay in question is the small black box seen in the centre of the picture.  It switches at the operating voltage of Class 50 auxiliaries, namely 110v DC which brings about the problem of how to find a modern equivalent.  Electronics is obviously one area where technology has progressed leaps and bounds in the near-half century since the Class 50 was constructed by English Electric and relays to operate at such high DC voltage, let alone such compact ones (it appears the original was custom-made for EE by ITT) are almost completely obsolete these days.  Most modern relays, even of a size too big to fit the case, would burn out very quickly if asked to switch 110v DC.

We thought about various ways to overcome the problem.  Inverting the current to AC, using an AC relay and then rectifying it back to DC was suggested but dismissed as impractical.  50030 Electrical Officer Andy Rowlands suggested using a spare NR28 relay, as used elsewhere in the locomotive to switch 110v DC.  It wouldn't fit in the box for the CU2 (and the CU2 is deliberately designed to be compact as it fits into a very tight space in the cubicle) but Andy reasoned it could be mounted externally and wired in.  We supplied IES with a couple of NR28s to test the theory and they agreed it would work but felt the new divert unit would need some circuit modification if it were to be used.  IES decided to have another look at the relay market and managed to source a relay from the US which has a 24v coil and can switch up to 220v DC.  IES ordered a number of these relays on our behalf and have now advised us that they have arrived and appear to work fine in our 110v DC application.

We now expect progress to be rapid on the rebuild of these electronic units.  IES have invited Andy to inspect the new relays in person the first week in March and if approved by us, IES expect to finalise the design within the next couple of weeks with production of the two units requested following imminently thereafter.

A full description of the electronic units in a Class 50, and how many of each type RRRG has, can be found in RRRG newsletter Issue 23 (Autumn 2011).  Since that article was written, we have acquired one original CU2 from another Class 50 owning group however we still intend to have two units built by IES to cover for possible future failures.

RRRG will be attending the Nene Valley Railway steam gala with our sales stand at Wansford station on February 23-24.  We will have our usual selection of books, DVDs and keenly-priced Hornby models on sale and we thank the NVR for extending us the invitation to attend their events once again this year.  Come along and say hello, there's a good lineup of steam power on show including 70000 Britannia, and you can chat to RRRG representatives about the state of the project and how you can help.

A few bits of news to report.

• The RRRG sales stand has been around the model fairs over the past month or so.  We have raised a reasonable amount but high pitch fees and the general climate prevailing at the moment don't help.
• Our online shop now features our full range of Hornby and Hornby Railroad models.  Take a look - there will hopefully be something to tempt you and at keen prices as well!
• A major addition to the website is a full archive of all the Group's newsletters (except the current issue; this will appear in due course but will be viewable by RRRG members only).  These form an excellent picture of the Group's progress and achievements over the years and we hope you will enjoy reading them.  If you're not already a member perhaps they will encourage you to join RRRG and help our cause?

We've been a bit quiet here whilst we all took it easy over the Christmas break.  Back to the grindstone now however! (At least for our regular day jobs!)  This weekend I made a few changes to the shop on the RRRG site.  I added a few new products and also comprehensively revised the Past and Present books in our used books section.  I added scans of a few sample pages from each one so you can see what you're buying, and also the maps from each volume showing the areas covered - again, so you know what you're buying!  The most significant change to the shop is the addition of second class postage options for some products and insured delivery for our higher value products.  I am personally a first class postage man, prepared to pay a premium for express service, but we realise that it makes sense to give the option of a cheaper service if you aren't insistent on having your items arrive quite so quickly.  This is only available for some items because items over 1kg in weight can't be sent second class, plus some models are more expensive than the insurance level offered by second class post.  However if an item from the shop is eligible for second class postage then the option will be presented when you check out.  We will be adding more merchandise over the coming days so keep checking back!